Silicon-carbon composite material, and preparation method and application thereof

A technology of silicon-carbon composite materials and carbon content, which is applied in the direction of electrical components, electrochemical generators, battery electrodes, etc., can solve the problems of restricting the migration rate of lithium ions, the reduction of charge and discharge efficiency, and poor material rate performance, etc., to achieve a good cycle Stable performance, reduced consumption, and good electrical conductivity

Active Publication Date: 2019-11-12
SHENZHEN DYNANONIC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, during the alloying reaction between silicon and lithium, the silicon material will undergo severe volume expansion (the volume change rate reaches 270% to 300%), which will easily lead to structural damage and pulverization of the active material during the cycle. It will also make the silicon material unable to form a stable surface solid electrolyte film or SEI film in the electrolyte. After the electrode structure is destroyed, the newly exposed silicon surface will form a new SEI film again, resulting in a decrease in charge and discharge efficiency and accelerated capacity fading.
On the other hand, the low intrinsic conductivity of silicon restricts the migration rate of lithium ions, resulting in poor material rate performance.

Method used

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  • Silicon-carbon composite material, and preparation method and application thereof
  • Silicon-carbon composite material, and preparation method and application thereof
  • Silicon-carbon composite material, and preparation method and application thereof

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preparation example Construction

[0067] see figure 1 , In one embodiment of the present invention, a method for preparing a silicon-carbon composite material is provided, comprising the following steps:

[0068] S01. Disperse the silicon oxide raw material into a mixed solution containing a dispersant, a metal catalyst, and a solvent, place it in a sand mill for nano-processing, and then dry and crush it to obtain silicon oxide nanoparticles;

[0069] S02. Mix the silicon oxide nanoparticles and asphalt in a mass ratio of 20:(1-4), and form a precursor after heating and stirring in a reaction kettle under an inert gas environment; the temperature of the heating and stirring process The curve is: raise the temperature to 250°C-350°C, keep warm for 1-3h, then raise the temperature to 550°C-650°C, keep warm for 2-6h;

[0070] S03, placing the precursor in a tube furnace, and sintering at a high temperature in an inert gas environment to obtain a crude silicon-carbon composite material;

[0071] S04. Perform ac...

Embodiment 1

[0074] A method for preparing a silicon-carbon composite material, comprising the steps of:

[0075] (1) Disperse 500g of the purchased silicon oxide raw material with a particle size of 1 μm in an ethanol solution in which 10g of polyvinylpyrrolidone and 3.26g of nickel nitrate hexahydrate are dissolved. The speed of the disperser is 1000rpm. After the dispersion is uniform, it is passed into a sand mill for grinding Until the particle size D90 is 300nm, the rotational speed of the sand mill is 3000rpm. The slurry obtained after sand grinding was dried and pulverized to obtain silicon oxide nanoparticles with a primary particle size of 300 nm.

[0076] (2) Add the collected silica nanoparticles and asphalt into the reactor at a mass ratio of 95:5, set the heating program at 250°C for 3 hours, 550°C for 3 hours, and knead the reactor at a stirring speed of 60rpm to obtain the precursor.

[0077] (3) The obtained precursor was sintered and disproportionated in a tube furnace u...

Embodiment 2

[0080] A method for preparing a silicon-carbon composite material, comprising the steps of:

[0081] (1) Disperse 500g of purchased silicon oxide with a particle size of 20μm in a deionized aqueous solution in which 10g of polyvinylpyrrolidone and 15.48g of nickel nitrate hexahydrate are dissolved. The speed of the disperser is 1000rpm. After the dispersion is uniform, it is passed into a sand mill for grinding. Until the particle size D90 is 300nm, the rotational speed of the sand mill is 3000rpm. The slurry obtained after sand grinding was dried and pulverized to obtain silicon oxide nanoparticles with a primary particle size of 300 nm.

[0082] (2) Add the collected silica nanoparticles and asphalt into the reactor at a mass ratio of 80:20, set the heating program at 350°C for 3 hours, and at 650°C for 3 hours, and knead the reactor at a stirring speed of 120rpm to obtain the precursor.

[0083] (3) The obtained precursor was sintered and disproportionated in a tube furnac...

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Abstract

The invention provides a preparation method of a silicon-carbon composite material. The preparation method comprises the following steps: (1) dispersing a silicon oxide raw material into a mixed solution containing a dispersing agent, a metal catalyst and a solvent, carrying out nano-treatment in a sand mill, and carrying out drying and crushing to obtain silicon oxide nanoparticles; (2) mixing the silicon oxide nanoparticles with asphalt according to a mass ratio of 20 : (1-4), and in an inert gas environment, carrying out heating stirring in a reaction kettle to form a precursor; (3) puttingthe precursor into a tubular furnace, and carrying out sintering at a high temperature in the inert gas environment to obtain a crude product of the silicon-carbon composite material; and (4) carrying out acid treatment on the crude product of the silicon-carbon composite material, washing the crude product to be neutral, and carrying out drying and collecting to obtain the silicon-carbon composite material. The preparation method is simple in process and can be used for industrial production; and the silicon-carbon composite material is good in electrical conductivity and has high cycling stability. The invention also provides the silicon-carbon composite material and an application thereof.

Description

technical field [0001] The invention relates to the field of lithium-ion battery materials, in particular to a silicon-carbon composite material and a preparation method and application thereof. Background technique [0002] Lithium-ion batteries have become a research hotspot in the field of new energy due to their excellent properties such as large specific energy, small self-discharge, high working voltage, no memory effect, and environmental protection. At present, the anode materials of lithium-ion batteries used in commercial production are mainly carbon materials with low and stable working potential and good cycle performance. However, the specific capacity of carbon materials is low, and the lithium storage capacity of lithium-ion battery anode materials is a key factor restricting its application range. [0003] Silicon has a large theoretical specific capacity (4200mAh / g), which is an order of magnitude higher than that of graphite-based negative electrode materi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/48H01M4/62H01M10/0525
CPCH01M4/366H01M4/483H01M4/625H01M10/0525Y02E60/10
Inventor 羊启发孔令涌朱成奔任望保
Owner SHENZHEN DYNANONIC
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